Comp truck lid

[V.W.Dave]

I am getting to the end of building my exo and I am scratching my head as to what to do for my roof. Its a soft top sierra.
My options
1) I do have a fiberglass front section that I can put on then build the exo around it.
2) I can leave the fiberglass roof off and make a tin roof
3) I can do a combo of the 2 above
4) just leave it open bars for the roof

If I build the exo around the fiberglass its going to stick up a little but it will be much cooler in the direct heat.
If I make just a tin roof it will look better and work fine but it will be hot as hell in the cab under direct sunlight.
Using both the fiberglass and tin will be best but it will make it sit really high and add weight up high.
If I leave it open bars will look the best but it will be a little wet if it rains and run the risk of sticks/rocks coming in the cab during a role over.
Just wondering if its worth keeping the fiberglass roof or not????
Here is a pic without the fiberglass roof on it.

[joshy]

if you are going to comp it think youll find most comps will specify needing sheeting over the roof incase of like you said rocks/sticks. Go with the fibreglass roof.

[V.W.Dave]

if you are going to comp it think youll find most comps will specify needing sheeting over the roof incase of like you said rocks/sticks. Go with the fibreglass roof.

I have looked into that. If a fiberglass roof is in plase the exo has to be on the outside and the fiberglass has to be over 5mm thick. This lid is a very old TJM one that is about 8mm thick.
But those rules change in the comps like Cliffhanger where you must have a factory roof or 4mm tin with cromo role bars.

I can always get the fiberglass roof out if I bar it on. All I would have to do is take the front windshield off and the roof will come out.

[sierrajim]

Fibreglass when hit tends to explode, go the alloy sheet.

[troopy94]

I run alloy sheet as a roof on my comp zook to save weight up high and it's still strong enough to have 3 people stand on it

[80's_delirious]

if you are worried about the heat under a metal lid, insulate the underside of it with a couple of layers of foil backed closed cell foam, its light weight, easily moulded to fit to a curve, and gives good thermal insulation, and it is cheap and can be bought with a self adhesive layer already on it.

[DUDELUX]

Have you considered perspex??

Im sure Ive seen some comp Zooks with perspex roofs at comps.

[V.W.Dave]

Have you considered perspex??

Im sure Ive seen some comp Zooks with perspex roofs at comps.

Good idea in theory but in one of my past life's I did a lot of work with perspex and when it does brake under pressure it likes to explode and is as sharp and is more dangerous then glass because it does not shatter it stays in large sharp pieces. If I used perspex it would have to be like 10+mm thick. Good thinking though. If it was tinted that would be cool in the sun too hmmmmmm maybe a price check is needed.

[80's_delirious]

Use Lexan instead, it doesnt shatter like perspex does, it gets used for things like drag racing windscreens, prison windows etc.

[atari4x4]

if you plan to comp it, study the rule book for the ones you want to enter... no point putting on something that isn't allowed

[offroadboss]

fibreglass shouldnt explode, it will just crack with a loud noise. id go the fibreglass for sure

[V.W.Dave]

I am only going to be doing willowglen, taperi and masters. I will have a read over the rules.

[rockcrawler31]

I say sheet metal with Dzus fasteners, with a foam underneath. easy to replace the sheet when it's munted, easy to remove with the fasteners for a recreational wheel, and you can transfer the fasteners over. Probably cheaper than any of the glass or plastic materials.

[Tim D]

Kevlar is the best i've seen, I've seen a couple of patrols in the winch seen years ago with Kevlar panels that flex, you get what you pay for.

[80's_delirious]

Kevlar is the best i've seen, I've seen a couple of patrols in the winch seen years ago with Kevlar panels that flex, you get what you pay for.

Kevlar is more rigid than Fibreglass of the same thickness/weight, cant remember the tech behind it, something to do with fibre structure? It means you can build things lighter/thinner and have the same stiffness. similar deal with Carbon fibre.

[DIRTY ROCK STAR]

2mm thick sheet and paint it matte black.

[thehanko]

Kevlar is the best i've seen, I've seen a couple of patrols in the winch seen years ago with Kevlar panels that flex, you get what you pay for.

Kevlar is more rigid than Fibreglass of the same thickness/weight, cant remember the tech behind it, something to do with fibre structure? It means you can build things lighter/thinner and have the same stiffness. similar deal with Carbon fibre.

kevlar and carbon exhibite quite different flex, kevlar being seen as soft (relatively) and tough, carbon being stiff but more brittle.

[V.W.Dave]

2mm thick sheet and paint it matte black.

Yes it is the easiest way but it also makes for a very hot head in the sun.

[rockcrawler31]

Dude it's virtually a buggy, you don't even have windows. How hot can it get

[V.W.Dave]

It has windows. I have full doors for it and I have a 6mm perspex thing that screws into the rear of the B-pillar. It will be a all weather buggy

Nahh honestly the minister of finance has 2 rules. She gets to drive it from time to time and it is warm in the cold weather. So with that I have to keep it so I can enclose it for the winter. Plus I plan to take it down south a few time in the future to see why they keep saying stock sierra diffs with gears can handle 35s.

[evanstaniland]

I'd go lexan if I were you, it would be practical in the way that If you were doing a steep down hill descent you will still be able to drive ahead of yourself by looking thru the roof!!

My 2c
Evan

[DIRTY ROCK STAR]

I'd go lexan if I were you, it would be practical in the way that If you were doing a steep down hill descent you will still be able to drive ahead of yourself by looking thru the roof!!

My 2c
Evan

steel sheet and a periscope!
and if the steel is too hot, which i think points to you being too soft... just install one of those whirly birds!
problem solved!

[mutilated]

What about Shade sail cloth?

[Big_DP]

steel sheet and a periscope!
and if the steel is too hot, which i think points to you being too soft... just install one of those whirly birds!
problem solved!

Photo shop please

[hyzook]

For Masters last year I did 3mm Alloy sheet. I got a half sheet and had them cut it to 1200x900, I wanted it to go from side rail above door to other side and from screen to roll bar with no gaps and to look like a normal roof. After marking one side where it needed rolling I placed the sheet with the edge hanging over a timber bench and slowly worked it over with a rubber mallet, Then trimmed that side before doing the same to the other. Once it was shaped and the front and rear trimmed I removed the front soft top retaining strip and using longer screws I fit it back on over the alloy and into the screen suround. The rear I simply riveted to the main roll bar, before fitting I covered the inside with a vinyl to match the interior which cuts down heat and makes it look factory. The soft top then fits over the top and you would never know its there. All up it cost around $120 and took me about 4 hours.

[V.W.Dave]

I have been looking into doing Lexan. But how thick does it need to be? With the connections I have I have been quoted $230 for a 4.5mm 1220x2440mm sheet or $253 for a 6mm, $210 for 3.8mm of the same size. To have it tinted its an extra $25 on every comp page I have looked it states that lexan (HIPS) can be used but they never give a min thickness.

[MADSHORT]

gidday
did you find out alloy or sheet metal thickness
need to do my roof
cheers
Gordon

[V.W.Dave]

every comp had different sizes but the most common was 4.5mm treated Lexan, 3mm alloy or 2mm sheet. (that is what TT runs) best to look in the rules for the comps you wanting to go to. One of the rules I read had something about if you use alloy you must have a bar in the center (between the driver and passanger) between the A-pillar hoop and the b-pillar hoop.

[biggsy]

Im using a product call Diabond sheeting.... Its compressed plastic with a aluminium coat... great to cut with 2,3,4m think

[jorgo]

I think polycarbonate sounds like the best idea. Strong, light and cool.
Expensive lid though i guess